Der Mann mit der Maschine M4 Eurorack Droid Expander Module (Motorised Faders)

DROID M4 motor fader controller with 4 faders

This module provides you with four motorised faders (aka flying faders) to be attached to your DROID master. You can attach up to 16 of these units (or any other DROID controllers) to one master, so the maximum number of faders on a DROID is 64. Below each fader is a touch button and an LED.

You can use the faders, the buttons and the LEDs in very flexible ways to control all parameters in your DROID patches, like steps of a sequence, volumes of channels of a digital mixer (controlled via MIDI with the X7), parameters of a large bank of envelopes, CV values that are organized in presets and much more.

The special thing about the motorized faders is that each fader can be assigned several functions or presets. When you switch the function, the fader moves to the exact position that corresponds to the current value. The usual Eurorack "picking up" of potentiometers or faders, where you never know exactly which value is currently set, is now a thing of the past.

Another unique feature is the "haptic feedback". If a fader is used, for example, in a sequencer to select a note from a scale, you can feel each individual note like an artificial notch. The fader intelligently creates these virtual grooves with its motor. This is very useful and very intuitive whenever you use the fader to select one out of several discrete values. Other examples are clock divider settings, the number of a preset, a waveform, a clock offset and much more. Due to the haptic feedback you don't need any display for seeing what you are doing. You can concentrate on making music and play very intuitively.

Another kind of haptic feedback is a kind of "pitch bend wheel", where the fader always pushes back to the center position by itself. Here the motor creates an artifcial spring. When setting analog values such as a volume or a filter cutoff, the fader then runs freely, of course.

Applications

The DROID plus the faders can be used for various applications - and due to the possibility of switching even at the same time! Here are some example:

• A multi track performance sequencer
• Use a MIDI controllable digital audio interface as mixer
• Control a bank of four envelopes with A, D, S, R each with just four faders
• Use the faders for CV presets
• Use the faders and their haptic feedback for live performing with pitch bends, ratcheting and all other crazy stuff

Power

Motor faders need much energy. Theoretically one single fader can draw up to 800 mA when at full power. That seems to be the main reason why nobody dared in bringing motorised faders into Eurorack so far.

We have solved that challenge by making use of the fact that the fader need their power always just for a very short time. The M4 unit comes with four big power tanks (called super caps) that are loaded with a low current but provide the full power when the faders need them. That way the maximum current of one M4 unit is limited. With jumpers on the back you can choose between a peak current of 350, 450, 500 or 600 mA.